In addition to any periods excluded pursuant to Code Section 17-3-2, if the victim is a person who is 65 years of age or older, the applicable period within which a prosecution must be commenced under Code Section 17-3-1 or other applicable statute shall not begin to run until the violation is reported to or discovered by a law enforcement agency, prosecuting attorney, or other governmental agency, whichever occurs earlier. Such law enforcement agency or other governmental agency shall promptly report such allegation to the appropriate prosecuting attorney. Except for prosecutions for crimes for which the law provides a statute of limitations longer than 15 years, prosecution shall not commence more than 15 years after the commission of the crime.